Polyvinylchloride modified by a graft copolymer of vinyl chloride onto polypentenamer

ABSTRACT

There are disclosed new, high-impact resistant compositions based on polyvinylchloride and comprising graft copolymers of vinyl monomers and certain rubbery polyalkenamers having a narrow molecular weight distribution. Unexpectedly, the graft copolymers function to improve the mechanical properties, more particularly the impact resistance, of the compositions, as compared to polyvinylchloride, per se. That polyvinylchloride tends to be brittle and to have relatively low impact resistance is well known. In the past, it has been attempted to overcome the brittleness of polyvinylchloride, and its relatively low impact resistance by incorporating various plasticizers with it. A problem has been the tendency of the plasticizers to &#39;&#39;&#39;&#39;bleed,&#39;&#39;&#39;&#39; a result of a basic incompatibility of the polyvinylchloride and the plasticizers available.

Unite States ate [1 1 Severini et al.

[4 1 Apr. 10, 1973 POLYVINYLCHLORIDE MODIFIED BY A GRAFT COPOLYWR OFVINYL CHLORIDE ONTO POLYPENTENAIWER [75] Inventors: Febo Severini;Alberto Valvassori, both of Milan; Alberto Pagliari, Saronno, all ofItaly [73] Assignee: Montecatini Edison S.p.A., Milan,

Italy 221 Filed: Feb. 23, 1971 21 App1.No.: 118,097

[30] Foreign Application Priority Data Feb. 24, 1970 Italy ..21025 N70[52] US. Cl. ..260/876 R, 260/23 R, 260/23 H, 260/93.l, 260/45.95,260/875, 260/884 51] Int. Cl. ..C08f 39/00 [58] Field of Search..260/876 R, 887, 897 c [56] References Cited UNITED STATES PATENTS 1H1971 Schuster ..260/881 10/1966 Kuhne ..260/876 R 8/1970 Manaresi etal. ..260/876 R 3,358,054 12/1967 Hardt et a1 ..260/876 R 3,334,1568/1967 Calentine et a1 ..260/876 R 3,444,268 5/1969 Beer ..260/876 RPrimary ExaminerSamuel H. Blech Assistant Examiner-John SeibertAtt0rneyP. Q. Peake et al.

[ ABSTRACT There are disclosed new, high-impact resistant compositionsbased on polyvinylchloride and comprising graft copolymers of vinylmonomers and certain rubbery polyalkenamers having a narrow molecularweight distribution. Unexpectedly, the graft copolymers function toimprove the mechanical properties, more particularly the impactresistance, of the compositions, as compared to polyvinylchloride, per

4 Claims, No Drawings POLYVINYLCIILORIDE MODIFIED BY A GRAFT. COPOLYMEROF VINYL CHLORIDE ONTO POLYPENTENAMER THE PRESENT INVENTION Thisinvention provides new compositions based on polyvinylchloride andcomprising graft copolymers of vinyl monomers, such as vinyl acetate orvinyl chloride,

positions are not brittle like polyvinylchloride and have anunexpectedly high impact resistance.

The polyalkenamers are obtained from cyclo-olefins, by ring-openingpolymerization thereof.

Processes for preparing the polyalkenamers are disclosed in, forinstance, US. Pat. Nos. 3,458,489; 3,549,607; 3,459,725; 3,449,310 and3,476,728.

The polyalkenamers used in practicing this invention are made up ofunits of the formula (CH2),, CH CH consist essentially of linear andstereoregular macromolecules having a high percentage of either thecisor transform, are rubbery or rubber-like, and are furthercharacterized in having a very narrow molecular weight distribution.

The graft copolymers can be prepared by known methods. As is known,graft copolymers may have a more or less high content of a homopolymerof the monomer used for the graft, depending on the conditions used inpreparing the graft copolymer.

The graft copolymers used in practicing this invention are free ofhomopolymers and have a high content of the rubbery polyalkenamer.

The side chains grafted onto the polyalkenamer, which are preferablypolyvinylchloride or polyvinylacetate side chains, and, therefore,similar to the macromolecules (polyvinylchloride) which form the matrix,insure the stability of the dispersion of the rubber (polyalkenamer)through the polyvinylchloride which is reinforced by the graftcopolymer. This is a result which cannot be obtained by mixing theunmodified rubber (polyalkenamer, per se) with the polyvinylchloride,since the polyalkenamers are similar to the known plasticizers in beingincompatible with polyvinylchloride. The rubbery polyalkenamers per se,when mixed with polyvinylchloride, separate from the mixture and migrateto the surface of manufactured articles formed of the mixture.

The graft reaction may be carried out according to known processes.Preferably, if the reactivity of the monomer and the reaction conditionsfavor it, the graft reaction is effected by chain transfer. The graftingreaction may be carried out in bulk, in emulsion, in solution or insuspension, or by mixed methods such as bulk-suspension,solution-precipitation, etc. Variations of the mentioned techniques maybe used.

The graft reaction is carried out in the presence of initiators.

Suitable initiators include organic peroxides, such as, for instance,acetyl peroxide, lauryl peroxide, benzoyl peroxide, and di-tert. butylperoxide. The initiator may also be a thermally unstable inorganiccompound such as, for instance, ammonium persulphate, or a thermallyunstable-azoic derivative such as azo-bis-isobutyrronitrile. Redoxsystems consisting of hydroperoxides and a reducing agent may also beemployed as the initiator.

I with particular rubbery polyalkenamers, which com- The amount ofinitiator used, calculated with reference to the total mass ofreactants, varies between 0.1 and 10 percent by weight. Preferably, itis comprised between 0.2 and 5 percent by weight.

The temperature for the graft copolymerization depends on the initiatorused and is in the range 0C to 100C. It is preferably carried out in thepresence of a suitable amount of a molecular weight regulator which maybe, for example, a mercaptan or other molecular weight regulating agent.

When the graft copolymerization is carried out in solution, the solventmay be an aliphatic hydrocarbon such as butane or n-pentane, acycloaliphatic hydrocarbon such as cyclohexane, or an aromatichydrocarbon such as benzene or toluene. Mixed solvents may be used.

The graft copolymerization of the vinyl monomer and polyalkenamer inaqueous suspension may be carried out by suspending a solution of thepolyalkenamer in the vinyl monomer in water, or by polymerizing thevinyl monomer in the presence of the rubber (polyalkenamer) suspended inwater in a finely divided form. In general, small amounts of suspendingagents are used, on the order of 0.2 to 1.0 percent by weight, based onthe weight of the reaction mass. The suspending agent may be ahydrosoluble organic polymer, such as polyvinylalcohol obtained bypartial or total hydrolysis of polyvinylacetate, methylcellulose,carboxymethyl cellulose, and so on.

The graft copolymerization in emulsion may be carried out directly inthe emulsion obtained by dispersing in water, in the presence ofsurface-active agent, the pseudosolution obtained by mixing thepolyalkenamer with a suitable solvent, or it may be effected in theaqueous emulsion remaining after distilling off the solvent, underreduced pressure, from the starting dispersion.

Anionic surfactants may be used in the emulsion process, such as, forinstance, sodium dodecylbenzene-sulphonate, or sodium oleate. Non-ionicsurfactants are also useful, including, for instance, the products ofreaction between alkylphenol and ethylene oxide. Also useful aremixtures of non-ionic and anionic surfactants, as well as sulphonatedderivatives of the products of reaction between alkylphenols andethylene oxide.

The graft copolymers of vinyl monomers and polyalkenamers comprised inthe compositions of this invention are reinforcing agents for thepolyvinylchloride.

In one preferred embodiment, the reinforcing agent is a graft copolymerof polypentenamer having a prevailingly (over 50 percent trans-vstructure with vinyl chloride and characterized by a chlorine content offrom 20% to 40%.

Analogous results are obtained using as reinforcing agent a graftcopolymer of polypentenamer having a prevailingly (over 50 percent)cis-struct'ure with vinyl chloride and characterized by a chlorinecontent of from 20 to 40 percent.

The compositions, in addition to possessing increased impact resistance,as compared to polyvinylchloride, are also highly transparent, and havea light transmission value comprised between 40% and The followingexamples are given to illustrate the invention and are not intended tobe limiting.

EXAMPLE 1 a. Preparation of the polyalkenamer Cyclopentene, throughwhich air at room temperature had been bubbled for an hour and a half,was polymerized during one hour at a temperature of -30 C, in thepresence of tungsten hexachloride and aluminum-diethyl monochloride in amolar ratio of 1 z 5. The molar ratio tungsten hexachloride/cyclopenteneamounted to l 2 120.

The polymerization was interrupted by the addition of methanol and thereaction mixture was then introduced into methanol containinghydrochloric acid. The polymer thus obtained was dissolved in benzenecontaining phenylbetanaphthylamine, the solution was filtered and thenpoured into the methanol. The coagulated polymer was suspended inmethanol containing 0.1 percent of betanaphthylamine, the suspension wasfiltered and the polymer was finally dried under a reduced pressure andat room temperature.

The polypentenamer obtained consisted of macromolecules havingpredominantly a trans structure and characterized by an intrinsicviscosity, determined in toluene at 30C, of 1.7 dl/g.

b. Preparation of the aqueous emulsion of polyalkenamers 100 g of thepolypentenamer obtained in- (a) were mixed with 900 g of toluene andmaintained under stirring at room temperature until a homogeneous pastymass was obtained.

To the pseudo-solution thus obtained there were added 12 g of asurfactant known by the commerical name of Fenopon Co. 436 (containing50 percent by weight of the ammonium salt of the sulphate of analkylphenoxy-polyethylenoxy ethanol) and, slowly, keeping the mass understirring, 1000 g of de-ionized water. The mixture thus obtained was thensubjected for minutes to the action of a mechanical emulsifier and thelatex thus prepared wasthen freed of the toluene by distillation underreduced pressure of a toluene/water mixture.

The latex thus obtained had a dry residue of 9.5% which corresponds to acontent in polypentanamer of 8.9%.

c. Graft reaction of the polyalkenamer Into a 1 liter glass autoclavefitted with an anchor stirrer, were introduced:

225 g of the latex prepared under (b),

0.22 g of sodium hexametaphosphate,

0.15 g of cumene hydroperoxide at 72%,

0.08 g of sodium formaldehyde-sulphoxylate, and

' then, after removal of the air by washing with nitrogen,

35 g of monomeric vinylchloride. The temperature of the thermostaticallystabilized bath in which the reactor is immersed, was brought up to 38Cand the reacstant of 60 to obtain a composition containing 9 percent byweight of the polyalkenamer. The mixture thus obtained, afterstabilization by the addition of 2 percent barium stearate and cadmiumpowder coprecipitate as a stabilizer, and of 0.1 percent of anantioxidant of the phenolic type and known by the trade mark of IRGANOX1076, for reducing the degrading effects on processing of theelastomeric phase, was homogenized in a roller mixer at the temperatureof 185C, and the products thus obtained were subsequently compressionmolded at a temperature of 180C. The specimens required for thedetermination of the mechanical properties of the material were obtainedfrom the compression-molded plates. In this example, and in thefollowing ones, the mechanical characteristics were determined accordingto the following ASTM standards:

ASTM D 256-56 ASTM D 785-62 Izod impact (notched) Rockwell hardness Themechanical properties of the mixture obtained according to this examplewere as follows:

Izod impact (notched) at 23C Rockwell hardness (scale L) EXAMPLE 2 18kg. cm/cm 62 Into a 2 liter autoclave provided with a mechanical stirrerand an oil-circulation heating circuit, were introduced:

g of deionized and boiled water,

50 g of a 5 percent solution of polyvinyl alcohol (Elvano 50-42 22 g ofthe polypentenamer obtained under (a) of Example I, in small pieces; andafter washing with nitrogen,

200 g of monomeric vinyl chloride.

This mixture was allowed to stand at rest, at room temperature, for 20hours, in order to promote the dissolving process and the swelling ofthe polypentenamer in the monomer. Thereafter, stirring was started, thereaction mass was heated up to 65C, and maintained at that temperaturefor 2 hours, after which a suspension of 0.76 g of benzoyl peroxide in350 g of deionized Izod impact at 23C:

15 Kg.cm/cm Rockwell hardness scale L:

The compositions of the invention may also include other vinyl polymers,in addition to polyvinylchloride, for example polystyrene.

The compositions of the invention can be used for any of the purposesfor which polyvinylchloride is used.

As will be apparent, changes and modifications in details may be made inpracticing the invention, without departing from its spirit. Therefore,we intend to include in the scope of the appended claims all suchchanges and modifications as will be obvious to those skilled in the artfrom the description and working examples given herein.

What is claimed is:

1. Compositions the essential ingredients of which are polyvinylchloride and a graft copolymer of vinyl chloride and a rubberypolypentenamer in which the polypentenamer content is from about 50 toabout 62 percent by weight, the amount of the polypentenamer in thecomposition being from 9 to 20 percent by weight.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Paten 3, 726, 946D April 10, 1973 Inventor(s) Febo Severini et 8.1

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Col. 3, line 3 (Example 1) "pracitcally" should be -prectical1y- Col. 6,line 4 (claim 2) "chloride" should read ch1orine- Signed and sealed this18th day of June 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents FORM PC9-1050 (10-59) USCOMM-DC scan-Pas 9 LLS. GOVERNMENTPRINTING OFFICE 2 l9, O36"l3"

2. Compositions according to claim 1, the essential ingredients of whichare polyvinyl chloride and graft copolymers of vinyl chloride andpolypentenamers having a chloride content of from 20 to 40 percent byweight.
 3. Compositions according to claim 1, characterized in that theessential ingredients thereof are polyvinyl chloride and graftcopolymers of vinyl chloride and polypentenamers having a prevailinglytrans-structure, said graft copolymers containing from 20 to 40 percentby weight of chlorine.
 4. Manufactured articles of the compositionsaccording to claim